| Exhaust nozzle is a key component of pulse detonation engine (PDE). It plays a critical role in converting the thermal energy of combustion gases in the detonation chamber to directed kinetic energy in the exhaust, so as to obtain maximum thrust performance.The nozzle designs and analysis for PDE poses a significantly greater challenge due to the transient nature of the flow field. This dissertation deals with the modeling and simulation of the PDE with different nozzles, the entire internal and external flow evolutions of different nozzles during a full cycle are investigated and propulsive performance is calculated. Some researchs have been done as follow:Based on the working principle and operating cycle process of PDE, two different analytical models for the performance of a single-cycle pulse detonation engine are established. The Performance of PDE was theoretically analyzed by using these models.Numerical simulations based on upwind total-variation-diminishing (TVD) scheme are carried out for single-pulse PDE with different nozzles. Five PDE nozzle geometries: straight extension, convergent nozzle, divergent nozzle, convergent -divergent nozzle, and ejector are evaluated. The flow evolutions of different nozzles during a full cycle are investigated, much effort was expended to analysis the effect of nozzle configuration on the system performance. The results indicate that the nozzles affect the chamber flow dynamics significantly and change performance through modification of the gas expansion process. Further analysis revealed that nozzle performance depends not only on its effect on the shock wave strength, but also on its effect on the downstream unsteady exhaust flows.The flow field interaction among detonation tubes sharing a common nozzle in a multi-tube PDE is explored. The evaluations are based on a two-dimensional analysis of single-pulse operation. Three common nozzle configurations are considered. The present study indicates that the common nozzles have a significant effect on flow field of detonation tube. In order to greatly enhance system performance, a PDE nozzle should be able to reduce exhaust shock strength and at the same time maintain high back pressure at the detonation tube exit. |
